johnson



(Mew E H JOHNSON INGANDESGING ELECTRIC LAMP.

No. 393,473. Patented Nov. 2'7, 1888.

UNITED STATES ED'WARD H. JOHNSON, OF NEW YORK, N. Y., ASSIGNOR TC THE EDISON ELECTRIC LIGHT COMPANY, OF SAME PLACE.

INCANDESCING ELECTRlC LAMP.

SPECIFICATION forming part of Letters Patent No. 3293, 273, dated November 27, 1888.

Application filed January 9,1886. Serial No. 188.091.

To all whom, it may concern.-

Be it known that I, EDWARD H. JoH-NsoN, of New York city, in the county and State of New York, have invented a certain new and 5 useful Improvement in Incandescing Electric Lamps,ofwhich the followingisaspecification.

When incandescent electric lamps are used in series with one another and with currents of high tension, and provided with cutout de- IO vices of the ordinary kind for closing a shunt around each lamp when its carbon breaks, difiiculty arises in the following way: If the carbon breaks, so that the current cannot pass through it, the high-tension current is apt to [5 pass across thevacuous space within the lampglobe from one side of the carbon below the point of breakage to the other side, forming an are. This passage being provided for the current, the cut-out fails to act, and the are there fore continues and follows down the carbon and the leading-in wires to the inner stem, which, being heated, becomes a conductor, and the are or current then passes through the glass to the wires within the stem, and so on down to the socket and cutout mechanism, so that the lamp, socket, and cut-out are all destroyed, as well as the continuity of the circuit.

The object of my invention is to provide means for stopping the are when such occurs before it leaves the lamp; and to this end my invention mainly consists in placing the wires outside the vacuum-globe, such wires being insulated from each other so close together that when the are reaches the point where the 3 5 wires are so placed their fusion by the heat of the arc will cause them to be fused or soldered together, whereby a good connection is made between them and circuit is closed around the carbon of the lamp, so that the series circuit is completed to the other lamps independent of the cut-out, my device forming an automatic cut-out whose operation is effected by the are itself; and my invention further consists in the various novel features and details of con struction hereinafter described, and pointed out in the claims.

To insulate the wires from each other, I prefer to employ upon one or upon each of them a thin covering of cotton or similar fabric,

which becomes carbonized by the heat of the (N0 model.)

are, and thereby assists in forming a good electrical connection between the wires. I may inclose both wires in a small tube of lead, tin,

or other readily fusible metal which will melt and itself act to solder the wires together. I prefer to twist the wires together for a short distance within the glass tube or stem; but they may instead be simply placed side by side, and if necessary held together by the tube placed around them or by any suitable wraping or binding.

Then the lamps constructed substantially as above described are connected in series, I prefer to employ in connection with each lamp electro magnetic cut-out mechanism, so thatif 6 the carbon breaks without any are being formed across it, which often occurs, such cut-out mechanism will act to close a shunt around the lamp and complete the series circuit.

My invention is illustrated in the annexed 7O drawings, in which- Figure 1 is a diagram of a portion of an electric-lighting system embodying my invention; Fig. 2, aviewofalamp with wires twisted together; Fig. 3, a larger view of the inner stern of this lamp afterthe arc has been formed and stopped; Fig. at, a view of a lampin which a metal tube is placed around the wires, and Fig. 5 an enlarged view showing the two wires as twisted together.

Like letters refer to corresponding parts in all the figures.

A is the sealed inclosing-globe of an Edison incandescing electric lamp.

B is the inner tube or stem, through which pass the leading-in wires a a, such wires being sealed in the glass of the stem at b.

C is the carbon filament, which forms the incandescing conductor. It is secured at c 0 to the leadingin wires in any well-known or 0 desired manner, preferably by electroplated joints. The lower end of the stem is closed by a cork stopper, (l, which keeps the wires in place.

In the form shown in Fig. 2 the wires a a 5 are twisted together in the tube B, as shown at a", so as to bring them close together for a considerable portion of their length. One or both of these wires are covered with insulating material, 6, as shown in Fig. 5, which insula- IOO tionis a light one, preferably of cotton or other carbonizable material, which will act in the manner already explained.

Fig. 3 shows the stem after the are has been formed and stopped,the wires a a downto the point at which they were twisted together having been consumed by the are; but at this point they are soldered together, as shown at f, by the fusion of the metal, and the circuit is therefore closed around the carbon, as has been set forth.

In the form shown in Fig. I the insulated wires are simply placed side bysidein contact and are inclosed by a tube, 9, of lead, tin, or other readily-fusible metal. The operation or effect of this arrangement has already been clearly explained, the metal tube melting and assisting to solder the wires together.

In connection with the lamps constructed as described I prefer to employ a suitable electro-Inagnetic cutout device, which may be such as is shown in Fig. 1. In this figure, L L is the line-circuit, in which any suitable number of lamps, A, are placed in series. Around each lamp is a shunt, h It, including the coils of an electro-magnet, E, whose spring-retracted armature-lever k is adapted to make and break at Z another shunt, m m. When the carbon filament breaks, if an arc across the filament should not be formed the magnet E is energized and its armature-lever closes circuit on on around the lamp, so as to maintain the linecircuit to the other lamps. The catch it looks the lever down upon Z, so that the shunt is kept closed until the broken lamp is replaced by a new one,when the catch is withdrawn by hand and the armaturelever is brought away from contact by its spring. It is evident that any other convenient and efficient form of cutout mechanism may be substituted for that shown and described.

My invention thus provides for both of the two contingencies which arise in the use of lamps in the manner explained.

If the carbon breaks and no arc is formed, 5 the electro magnetic cut out closes circuit around the lamp. If the are is formed,it itself causes a short circuit within the stem of the lamp.

\Vhat I claim is 1. In an incandescent electric lamp, the leadingin wires twisted one around the other and insulated electrically from each other at a point outside the vacuum, substantially as set forth.

2. In an incandescent electric lamp, the leading-in wires twisted one around the other and insulated electrically from each other ata pointbetween the vacuum-chamber and the eX- tremity of the lamp, substantially as set forth.

3. In an incandescent electric lamp, the leading-in wires twisted one around the other and insulated electrically from each other within the glass stem of thelamp,substantial1y as set forth.

l. In an incandescent electric lamp, the leading-in wires situated in soldering or fusing proximity and electrically insulated from each other at a point outside the vacuum, substantially as set forth.

5. In an incandescent electric lamp, the leadingin wires situated in soldering or fusing proximity at a point outside the vacuum and insulated from each other by carbonizable material, substantially as set forth. 7 5

This specification signed and witnessed this 2d day of January, 1886.

EDWARD H. JOHNSON.

In presence of A. W. KIDDLE, E. O. ROWLAND. 

